Britain's prison system churns out thousands of prisoners addicted to methadone, according to a thinktank with close links to the Tories.

The Centre for Policy Studies claims that many inmates on the heroin substitute have little chance of being weaned off. The CPS obtained figures from the government showing a 57% increase in the number of prisoners on methadone "maintenance" programmes, up from 12,518 in 2007 to 19,632 last year.

Last year, 45,135 prisoners were placed on detoxification programmes which mostly involved them being placed on methadone. Of 140,000 prisoners passing through the jail system last year, more than 60,000 would have received methadone or another substitute, buprenorphine.

The rise is in part due to the roll-out of the Integrated Drug Treatment System (IDTS), part of the government's strategy to break the link between crime and addiction. But it has led to concerns that prisoners are swapping one addictive drug (heroin) for another (methadone) with little chance of getting clean.

Kathy Gyngell, policy analyst with the CPS and author of The Phoney War on Drugs, said: "The government is creating a huge… social problem because nobody is putting money into alternative programmes."

Gyngell said alternative psychological-based treatments were needed. In contrast to the thousands of prisoners on methadone, Gyngell pointed out that only 850 had been placed on a 12-step detoxification programme that involves talking therapies and has been shown to work.

A Department of Health report noted: "The home affairs select committee recommended that methadone maintenance should be available across the prison estate. There has been considerable unease around this practice within the Prison Service."

Many drugs experts argue, however, that methadone plays a key role in tackling addiction. "It would be a mistake to rule methadone out of recovery altogether," said a spokesman for the drugs charity Addaction.

A Ministry of Justice spokesman said the increase in methadone prescriptions was a result of the government's commitment to tackling drug dependence among prisoners.